Tooth decay (dental caries) is one of mans most common diseases. It is now well established that diet plays a central role in the development of dental caries. Numerous studies involving man, animals and laboratory investigations have clearly shown a relationship between a frequent consumption of fermentable carbohydrates, particularly sucrose, and the high prevalence of dental caries. Because sucrose is the sugar eaten most often and in the greatest quantity it is regarded as uniquely associated with dental caries. This, also, suggests that sugar confectionery compositions, which usually contain high concentrations of sucrose, and conventional chocolate compositions, which usually contain up to about 50% sucrose, are suspected to increase the prevalence of dental caries.
Dental caries is a multifactorial disease resulting from the action of oral bacteria on a suitable carbohydrate substrate producing acidic products which cause loss of minerals (demineralization) of dental enamel. If demineralization continues and calcium and phosphate diffuse out of the tooth into the oral environment then visible decay occurs and eventually a cavity forms. This process may be arrested and even reversed in the presence of fluoride along with calcium and phosphates. This is called remineralization. In simple terms the tooth decay equation is as follows:
______________________________________ Plaque Fermentable Organic + .fwdarw. Bacteria Carbohydrates Acids Organic Tooth + .fwdarw. Acids Mineral Demineralization ______________________________________
Initiation of caries usually involves dental enamel. Some lesions may start in exposed dentin and cementum. The mineral part of enamel, dentin and cementum consists mainly of a calcium-phosphate-carbonate phase with the inclusion of smaller concentrations of trace elements the most significant of which is fluorine. The crystalline structure of enamel is similar to a mineral called hydroxyapatite, Ca.sub.10 (PO.sub.4).sub.6 (OH).sub.2, which is highly susceptible to acid demineralization.
Oral aciduric bacteria especially Streptococcus Mutans, metabolize suitable substrate such as sucrose, glucose, fructose, maltose, or other fermentable carbohydrates producing acidic metabolites. The main organic acids formed are lactic, formic, propionic, and acetic. As a result the pH of bacterial dental plaque on dental tissue may drop to a level that causes loss of mineral salts from enamel. Pathogenic bacteria enter the porous demineralized areas and the cycle of formation of carious lesions continues.
It is known that administration of fluoride calcium, phosphorus and magnesium can effectively reduce the prevalence of dental caries. These minerals may be applied systemically or topically. The main source of systemic fluoride is ingestion of foods which naturally contain some fluoride ion, from ingestion of fluoridecontaining supplements, and from drinking fluoridated water. Systemic administration of fluoride results in uptake of fluoride by the tooth through the pulp and other blood supply sources. Fluoride in enamel is known to limit demineralization of the tooth enamel and to promote its remineralization into a stable fluorapatite crystal structure corresponding generally to the formula Ca.sub.10 (PO.sub.4).sub.6 F.sub.2 which exhibits greater caries resistance. However, some jurisdictions do not permit fluoridation of water supplies and in any event many individuals susceptible to dental caries, especially younq children, do not drink sufficient volumes of fluoridated water on a daily basis to afford an adequate fluoride dosage. Fluoride ingested in food provides variable and usually inadequate dosages, while the use of fluoride containing supplements should desirably be permitted only under professional care to avoid problems of under dosage or over dosage resulting in fluorosis.
Local or topical application of fluoride may be achieved by application of fluoride containing gels or solutions and by use of fluoride containing dentifrices. However, topical application of fluoride has been considered to result primarily in a CaF.sub.2 precipitate that leaches away readily and results in only a small secondary production of fluorapatite. To be effective, topical fluorides have to be frequently applied as in the use of fluoridated dentifrices. Optimal benefits from fluoride accrue when systemic fluorides, e.g. from ingesting fluoridated water, are combined with the use of topical fluorides as when using fluoridated dentifrices.
Even though there has been considerable reduction of tooth decay generally in western countries over the last 25 years, the occurrence of root caries is still a significant problem among dentate adults in western countries. In Third World countries tooth decay remains a general problem. Accordingly there exists a need for an effective means of preventing or significantly reducing the prevalence of dental caries among consumers of sucrose and other fermentable sugars, sugar confectionery, and chocolate.